1. Field of the Invention
The invention relates to a cutter assembly for mowing apparatus. The invention is more particularly concerned with a sickle guard for a cutter assembly of mowers. The cutter assembly comprises a sickle guard having at least one guard, wherein each guard comprises a guard body and an upper lip secured to the guard body, wherein between the guard body and the upper lip is provided a knife slot to receive knife sections secured to a reciprocable knife back, wherein each guard body has a ledger surface facing the knife sections and with lateral cutting edges, wherein each knife section is provided with a bottom face and lateral facets defining knife section cutting edges, wherein each guard is releasably secured at least by its guard body to a cutter bar, and wherein hold-down means are provided for holding down the knife sections in the direction towards the ledger surface of the guard bodies.
2. Description of the Prior Art
In one known sickle guard of this type (GB-A-1155464) cast or forged hold-down clips 13 are arranged at spaced intervals along a mounting member 10. Each clip 13 is T-shaped in plan view and is fixed by means of two guard mounting screws 18 to the cutter bar 10. A forwardly extending portion 43 has an undersurface 45 arranged to come into sliding contact with the upper faces of the knife sections 31. The clips 13 and their assembly and possible adjustment perpendicular to the upper faces of the knife sections 31 are costly and heavy.
From U.S. Pat. No. 3,722,196 it is known to divide each hold-down clip 21 into a mounting flange 23 and a hold-down arm 22 which is linked thereto at 39 and 40 so as to be capable of being raised and lowered. By means of an adjustment screw 43 inserted into the rearward end of the hold-down arm 22 and engaging at 44 against the cutter bar 11, there is a minimum distance between a lower guide face 41 of the hold-down arm 22 and the knife sections 19. This design requires increased expenditure.
From the French patent application 2546367 A1 it is known to adjust the height of the knife slot 62 so that instead of an upper lip, one has a separate upper portion 54 of the sickle guard 12 which is able to be raised and lowered on a mounting screw 14. The upper portion 54 has a fixed support runner 70 behind the screw 14 and an adjustable support screw 68 in front of the screw 14. The supports 68 and 70 rest on a carrier plate 48 which is supported on the cutter bar 10 by means of a spacer plate 14. This design is associated with particularly high manufacturing and assembly costs.